1. Field of the Invention
The present invention relates to a liquid-droplet jetting apparatus which jets liquid droplets, and a method of producing the liquid-droplet jetting apparatus.
2. Description of the Related Art
In an ink-jet head which jets ink from nozzles onto a recording paper, when ink is adhered around an ejecting port of a nozzle when droplets of ink are jetted, there is a possibility that, due to the adhered ink, liquid droplets which are jetted subsequently fly in an incorrect direction (bending), and/or there is a variation in a volume of liquid droplets and a velocity of liquid droplets, thereby lowering the printing quality. In view of this, in a general ink-jet head, for preventing the ink from adhering to a portion in the vicinity of the ejecting port of the nozzle, a liquid repellent film (ink repellent film) which prevents the ink from adhering in the vicinity of the ejecting port of the nozzle is provided on a liquid-droplet jetting surface on which the ejecting port of the nozzle is arranged.
However, the recording paper as an objective onto which the liquid droplets are jetted is transported by leaving a very small gap (of about 1 mm, for example) from the liquid-droplet jetting surface. Therefore, there is a possibility that the liquid repellent film is damaged such that the liquid repellent film is exfoliated due to the contact of the recording paper or the like with the liquid-droplet jetting surface. In addition, while wiping the liquid-droplet jetting surface by a wiper to remove ink and/or dust adhered to the liquid-droplet jetting surface, there is a possibility that the liquid repellent film is damaged by friction with the wiper. Due to such factors, when the liquid repellent film around the ejecting port of the nozzle is damaged, the jetting direction of the liquid droplets is bent, and the printing quality is lowered.
In view of this, an ink-jet head which is capable of preventing the damage to the liquid repellent film formed in the vicinity of the ejecting port of the nozzle has been proposed. For example, in an ink-jet head described in Japanese Patent Application Laid-open No. 2004-255702, a portion of a nozzle plate around the ejecting port of the nozzle is pressed by an elastic body from a side of a surface of the nozzle plate, and a recess is formed in this portion. On the other hand, in an ink-jet head described in Japanese Patent Application Laid-open No. 2003-276204, the portion of the nozzle plate around the ejecting port of the nozzle is partially removed by a laser processing or an etching, and a recess is formed. Due to the recesses, the liquid repellent film formed in the vicinity of the nozzle hardly comes in contact with the wiper which is operated or activated during wiping, or with the recording paper which is transported closely to the liquid-droplet jetting surface, and the damage of the liquid repellent film is prevented.